Survey of the experiences in particular with the prototype of the CWD 2000 windmill at the Technical University Eindhoven from May 1983 until December 1985

(1)

Survey of the experiences in particular with the prototype of

the CWD 2000 windmill at the Technical University Eindhoven

from May 1983 until December 1985

Citation for published version (APA):

Nat, van der, A. L. J. M. (1986). Survey of the experiences in particular with the prototype of the CWD 2000 windmill at the Technical University Eindhoven from May 1983 until December 1985. (TU Eindhoven. Vakgr. Transportfysica : rapport; Vol. R-810-D). Consultancy Services Wind Energy Developing Countries.

Document status and date: Published: 01/01/1986

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Survey of the experiences in

particular with the prototype of the CWD 2000 windmill at the

Technical University Eindhoven From May 1983 until December 1985

. Ad v"d. NAT

November 1986

WIND ENERGY GROUP

Technical University Eindhoven Faculty of Physics

R 810 D

Laboratory of Fluid Dynamics and Heat Transfer P.O. Box 513, 5600 MB Eindhoven, the Netherlands

CONSULTANCY SERVICES P.O. BOX 85

WIND ENERGY 3800 AB AMERSFOORT DEVELOPING COUNTRIES THE NETHERLANDS

B 1 BL. TECHN I SCHE UNIVERSITEIT

(3)

CONTENTS

1. Introduction

2. CWD 2000 introduction

3. Summary of field experiences with the the CWD 2000 windmill

4. A few adds and remarks

5. Cumulative measurements Page 1 2 5 27 27

(4)

1 1. INTRODUCTION

In this report a survey is given of the experiences on the testfield at the Technology University Eindhoven.

The windmill testfield is illustrated in fig. 1 •

.

~,

..

TIIP .at I

- t -_,

A description of the mills presently installed on the Eindhoven testfield.

(5)

2

Location 1

No windmill has been installed at this moment.

LocatioTI 2

Name of the windmill Rotor diameter

Height of the tower Safety system

Pump Capacity Stroke

Design tip speed ratio Number of blades

Depth of the well

Capacity of the vessel

Location 3

CWD 5000 5000 mm 12 meter

overspeed control by yawing, activated by means of side vane with manually

activated furling device

single acting piston pump with a bore of 1521 mm

521 m3/day at a wind speed of 4,5 m/sec and 20 meter lifting head

821-110-140-170-2021 mm Ad = 1.,8

8

30 meter about 4 rna

Climbable THE mast. Height of the mast 10 meter, in use for installation of anemometer and wind vane and also pressure vessel.

LocatioTI 4

Pump Capacity stroke

Depth of the well

Location 5

Height of the tower Safety system Pump Capacity Stroke CWD 27421 2740 mm 5,5 meter

overspeed control by yawing activated by side vane and hinged tail vane with

manually activated furling device suction pump with a bore of 145 mm

35 m3/day at a wind speed of 4 m/sec and

1m

meter lifting head

adjustable from 0 to 60 mm Ad

=

2 6 221 meter CWD 20210 2000 mm 6,5 meter

overspeed control by yawing activated by eccentric rotor and hinged side vane suction pump with a bore of 65 mm

35 m3/day at a wind speed of 3,5 m/sec and 5 meter lifting head

(6)

Depth of the well

Location 6

~d

=

1,35 b

3

open well, level varies with the ground water level between 1 and 2 meter

Kaal van der Linden mast, climbable, height 12 meter, in use for testing: anemometers reed switch type at b m - 9 m - 12 meter; wind vane at 12 meter; temperature meter at b meter.

Also installed is the pressure vessel of the CWD 2000 windmill at 3,5 meter and the pressure vessel of the CWD 51211210 HW windmill at

12 meter height.

LDcation 7 '

Pump Capacity Stroke

Depth of the well

LDcation 8

CWD 5000 HW 5121121121 mm 6 meter

overspeed control by yawing activated by side vane and ecliptic tail vane with manually activated furling device

single acting piston pump with a bore of 115 mm

19 ma/day at a wind speed of 4,5 m/sec and 54 meter lifting head

adjustable from 0 to 120 mm

Ad

=

2

8

5121 meter

Telescopic non climbable measuring mast <Natural Power} with a height of 12 meter in use for testing anemometers.

(7)

2. CWD 2000 INTRODUCTION i _ _ _ _ _ _ signal tower pipe reed switch signal out - magnet

Water flow meter

4

reed switch magnets

.. rotor shaft

yaw speed counter

di gi t.al signal

(8)

5

3. SUMMARY OF FIELD EXPERIENCES WITH THE CWD 2000

Date 198.3.Q5.11

The windmill has been erected (10 days) with the help of a winch. See-drawing

winch tower

After erection i t appears that the windmill has a bad starting behaviour.

The windmill starts at 4 m/sec but i t should start at 2.5 m/sec. The cause is probably friction in the wooden bearings of the

rocker army pump rod and crank rod.

The cause of the friction is the incorrect manufacture of the rocker arm.

The axes of the rocker arm are not parallel. See drawing.

The axle lines are not parallel

Also the shaft taps are too short so the pump rod is clamping on the rocker arm.

See drawing.

pump rod

clamping here

(9)

6

When the windmill is running the tower is bending. For direction, of move; see drawing.

\

Pump has not been installed.

Date 1983,,05,,19

• tower is moving in this direction

The pump has been connected now to the windmill. However the starting behaviour is bad

±

4 m/sec. Stroke maximum 100 mm.

Water level 1,60 meter below ground level. No pressure height.

Date 1983.06.17

A smaller cup for the piston of the pump was made. The old one had too much friction.

The cause of a bad starting behaviour is also the friction of the wooden bearings so the diameter was made a little larger and the length of the wooden bearings was shorted.

See drawing.

old situation

(10)

7 The starting behaviour is ok, now the windmill is starting at

~ 2,5 m/sec. The tower was made more stiff now (see remark date 1983.05.11)

An other improvement is a climbable tower. See drawing.

old tower

water level 1,50 below ground level stroke 50 mm

no pressure height

(11)

B

Date 1983.07.01

The starting behaviour of the windmill is ~ 3.75 m/s which is too high.

The cause is too much friction of the wooden bearings of the rocker arm and pump rod.

The wood has soaked up water so the diameter has become smaller. Water level 1,50 m

Stroke maximum 100 mm No pressure height.

Date 1983.07.07

The stroke was changed from 100 mm to 50 mm so the windmill is

starting at 2,5 m/s. /

This means that the wooden bearings are running in. Water level 1,50 m.

Stroke 50 mm.

No pressure height.

Date 198·3 .. 08.04

The water flow unit was connected to the windmill. A pressure vessel was placed in the KvdL mast. Pressure height is 3,50 meter.

Reading water flow meter 25 m3 •

Water level 2,10 m. Stroke 50 mm. See drawing. water out

1

_{looking glass} air separator

non return valve <t-- water inlet

water filter water flow meter

frame

Pate 198.3.08.12

Suddenly the starting behaviour of the windmill became worse

after inspection i t appeared that the starting hole in the piston was stopped up by a little stone. After cleaning of the starting hole the windmill is running ok.

(12)

Starting at 2,5 m/sec.

Reading water flow meter 38 m3 _• Water level 2 meter.

Pressure height changed from 3,5 m to 4 meter.

h t e 19~_08.U

Experiment with piston without a leather cup.

The piston is made of synthetic material (teflon) the cylinder is made of brass. There is a slit between the piston and the

cylinder which has the same function as the starting hole in the usual piston.

See drawing.

cylinder

0.05 mm Water level 2,00 m.

Pressure height 4 meter. Stroke 50 mm.

However during testing of the pump i t appeared that the piston sticked in the cylinder. The cause was an unroundness of the brass cylinder and/or probably the sucking up of water of the teflon piston.

Teflon can suck up water up to 57.0

Date 1983.09.01

The synthetic piston was made a little smaller so the sticking of the piston is over now. However, the slit between piston and

cylinder is too large now.

The pump delivers too less water and the windmill is starting too early at ~ 1,5 m/sec. It was decided to use the piston with a

leather cup running in the brass cylinder. Pressure height 4 meter.

Water level 1 meter.

Reading water flow meter bO m3 •

Stroke 50 mm.

Date 1983.10.05

Revolution counter was mounted on the rotor shaft. See drawing.

(13)

10

...

Anemometer and wind direction meter have been mounted now. Pressure height 4 meter.

Water level 1,60 meter below ground level. Reading water flow meter 114 m3 •

Stroke 50 mm.

Date 1983.10.12

The pump is leaking water along the packings of the cylinder. So air is coming on the suction side of the pump which gives a bad water output.

Pressure height 4 meter.

Stroke 50 mm.

Date 1983.10.26

Measurements with a pvc cylinder and usual piston were started. Therefore a new pvc cylinder and a piston with a new leather cup have been mounted diameter 0 63 mm.

The windmill starts now at + 2,5 m/sec. and delivers 0,75 l/sec. at max. rpm which is ok.

Pressure height 4 meter.

Water level 1,60 meter below gound level. Reading water flow meter 143 m3 •

Stroke 50 mm.

Date 1983.11.02

Because of frost the glass of the water flow meter has been broken.

After changing of the glass everything is working ok. Pressure height 4 meter.

Water level 1,60 meter.

(14)

11

Date 1983~11.11

The pump delivers no water. After priming of the pump i t works again.

The cause probably was a leaking foot valve caused by dirt. Pressure height 4 meter.

Stroke 50 mm.

Date 1983,11,17

The suction and pressure line were removed from the CWD 2000 well and placed in the CWD 2740 well.

The meaning of this is to pump water from a closed well (no ground water). In order to protect the water flow meter against frost anti freeze was added to the water in the CWD 2740 well.

(One part anti freeze to 10 parts water gives a protection t i l l

- a-c.)

The pressure vessel was disconnected from the windmill so i t is no longer possible that there is running water over the top of the tower.

Pressure height 0 meters.

Water level 2 meter below ground level. Reading water flow meter 163 m3 _•

Stroke 50 mm.

Date 1983.11.24

The water level of the well has been changed. The suction height is 4,5 m.

This to compensate the pressure height of 4 meters. Pressure height 0 m.

Water level 4,5 m.

Stroke 50 mm.

Date 1983.11.29

After standing still 3 a 4 hours the windmill delivered no water, the cause being a small hole in the suction line.

After sealing up i t was ok.

It appeared that the counter mechanism of the water flow meter had been worn out completely.

The cause probably being sand from the well.

There was mounted an other water flow counter type 20 m. Reading of this meter 1010 m3 •

Pressure height 0 m.

Water level 4,5 m below ground level. Reading water flow meter 1010 m3 •

Stroke 50 mm.

Date 1984.02.03

The reed switch of the rpm counter was broken. The cause being moisture and corrosion. After mounting a new one the rpm counter is working ok.

Pressure height 0 m.

(15)

Reading water flow meter 2781 ? Stroke 50 mm.

Remark the 2781 should be 1781.

The reading mechanism has been making a mistake.

pate 1984 .. 02.10

12

A new cable was mounted from the head of the windmill to the central box on the ground.

Because the windmill had turned several times around his axis the cable was broken.

A yawing speed counter was mounted together with a pressure pick up for measurements of the dynamic pressure in the pump.

See drawing.

connected to ~he.

head of the windmill

digital signal

4

. .

~

electronic box signal producer wheel _signal rubber 0 ring tower pipe electronic box signal transformer. signal

-. water out----.-.-.,

..

1·

pressure : .. t==#:=~ magnet pump rod piston, foot valve wheel groove

J

_{water inlet} under pressure

(16)

Pressure height 0 meter Water level 4,5 meter

Stroke 50 mm.

Date 1984.03.0J

13

The suction line of the windmill was placed back in the open (ground water) well under the CWD 2000.

Pressure vessel was mounted again, pressure height is 5,5 meter now.

New flexible hoses have been mounted. Pressure height 5,5 meter.

Stroke 50 mm.

Date 1984.03.29

By high wind speed (up to 10 m/s) there was water running out of the tower top_

The cause probably being the pressure vessel and resistance of the water measuring system.

'The counter mechanism of the water flow meter was cleaned. Pressure height 5,5 meter.

Reading water flow meter 1989 m3 _•

Stroke 50 mm.

Date 1984.04.26

The rotor shaft is running loose in its bearings so the excenter is running against the head frame of the windmill.

The result is a bad starting behaviour ~ 4 m/sec. and a lot of noise.

The cause was the clamp rings in the ball bearing which are running loose caused by jamming of one of the ball bearings of the main shaft.

The cause of the jamming of the ball bearing was, that there was no grease in the bearing house.

Pressure height 5,5 meter.

Stroke 50 mm.

pate 1984.05.10

After dismounting of the windmill in order to paint i t the following faults appeared.

a. The wooden bearings were complete worn out.

The crank pins of the rocker arm are also worn out.

The cause being defective lubrication by ineffective grease cups.

b. The rotor shaft bearings are worn out.

The cause being defective lubrication by no grease in the bearing house.

We manufactured new crank pins and made another lubrication system.

(17)

The grease cups were replaced by grease nipples. See drawing Old situation grease chamber . rocker arm New situation grease nipple

Pressure height 5,5 meter. Water level 1,80 meter.

Reading water flow meter 2118. Stroke 50 mm.

Summary repair CWD 2000

Reasons for overhaul

rocker arm

a. The bearings of the rocker arm were worn out.

b. The ball bearings of the rotor shaft were worn out. c. The windmill needed painting.

Overhaul experiences

a. The wear of the rocker arm. See drawing

(18)

rocker arm head frame

15

wear

pump rod F rotor

b. The wear of the rotor shaft. See drawing.

bearings

clamp bush

rotor shaft

Note: The bearing house had not been filled with grease. c. The ball bearing of the exenter had not been filled with

grease.

But this bearing has not been damaged. d. The painting of the tower is still ok.

We painted the windmill for reasons of estetics. e. There was no wear on the pump rod guide.

(19)

pump rod

16 tower pipe

bold M12

f. The condition of the piston and valves was ok.

Overhaul activities

a. Manufacturing of new crank pins for rocker arm and head frame. b. Manufacturing of new wooden bearings for rocker arm and pump

rod.

c. Manufacturing of new rotor shaft.

d. Removing of old crank pins from rocker arm head frame. See drawing

grind this away

/

\

rocker arm chaser chaser wooden bearings rocker arm rocker anT

(20)

17 e. Removing of wooden bearings.

f. Grinding of ~he windmill and spraying wi~h correless pain~, and Sikkens car pain~ (whi~e).

g. Welding of new crank pins in ~o ~he rocker arm wi~h special care ~o ~he parallism of the crank pins.

h. Pressing of new wooden bearings in rocker arm and pump rod, and making of bearings a~ ~he righ~ size.

i . Moun~ing of ~he head frame and ~he bearing houses and filling of them with grease.

j . Manufac~uring of new packings for the pump. k. Moun~ing of the pump under the windmill.

Moun~ing of ~he head frame on ~he windmill. Hounting of the ro~or.

Used .aterials at the overhaul

*ring spanner Date 1984.06.21 10x11 12x13 16x17 18x19 32 hammer drift grinding-machine welding-equipmen~ scissors sanding paper

pain~ + spray gun packing material

The overhaul has been finished now, windmill is running ok. The windmill s~ar~s at 2,5 m/sec.

Moun~ed a new reed swi~ch of ~he rpm counter the old one was broken.

Pressure heigh~ 5,5 me~er.

Reading water flow me~er 2132 m3 •

Water level 1,80 m. Stroke 50 mm.

The windmill stows the wa~er to the ~op of the ~ower where i t is running over.

Cause being probably ~he resistance of ~he wa~er flow me~er. The wooden bearings are running s~uck.

Cause being swell of the bearings by the water from the top of ~he ~ower. Windmill starts now at 4,5 m/sec.

Pressure height 5,5 meter. Water level 1,80 meter.

Reading wa~er flow meter 2179 m3 _•

Stroke 50 mm.

Date 1984.07.19

A collecting vessel has been installed in the return line. The water flow meter in the pressure line has been removed.

(21)

This reduced the resistance of the pressure line. See drawing.

water

1

inlet

water flow meter

The advantage of this system

There is now resistance in the pressure line. The system is not sensitive to frost.

The disadvantage of this system

18

There is a reaction time of

±

1 a 1 1/2 min. between delivery of water from the windmill and measuring of the water.

Pa.te 1984.07,,26

We have changed the water measuring system to reduce the time between delivery of water from the windmill and measuring of the water.

(22)

19 See drawing water inlet concrete trough ~ well

)77'»1

I'

water flow meter

Advantage of this system:

- Reaction time between delivery of water from the windmill to measuring of the water is now

±

30 a 45 sec. (There is more pressure over the water meter.)

- Water flow meter within better reach. Pressure height 5,5 meter.

Water level 1,70 below ground level. Reading flow meter

(23)

20

pate 1984.09.13

The windmill is starting at 4.5 m/sec. which is too high caused by the swell of the wooden bearings.

Date 1984.04.10

The windmill has been Jayed down to make the hole in the wooden bearings a little larger.

The clamping of the bearings should be over now.

Date 1984.10.11

The windmill has been erected. Stroke is max. 100 mm.

However, by the large water flow the water is running over at the top of the tower. To prevent the running over of the water we decided to place the pressure vessel 0,5 meter lower.

Windmill starts at

±

2,5 m/sec. Pressure height 5,0.

Water level 1,60 m.

Reading water flow meter Stroke 100 mm.

Date 1984.10.18

Water is still running over at the top of the tower of the windmill.

We decided to place the pressure vessel 0,5 meter lower. Pressure height 4,5 meter.

Water level 1,60

Reading water flow meter Stroke 100 mm.

Date 1984.11.01

The suction and pressure line have been placed in the well of the CWD 2740 windmill.

Now we can control the suction height.

Water is still running over the top of the tower (Probably the pressure line of 1" is too thin.)

We decided to place the pressure vessel 1 meter lower. Pressure height 3,5 meter.

Water level 5,5 meter below ground level. Reading water flow meter 1340 m3 _{(new start)}

Stroke 100 mm.

Date 1984.11.15

The windmill starts at

±

5 m/sec. which is too heigh. Caused by the wooden bearings of the rocker arm.

Date 1984.11.28

We have done an experiment to see where the friction, responsible for the heigh starting wind speed, is coming from.

The piston was replaced by a weight equal to the piston load. The wooden bearings were cleaned and filled with grease.

(24)

21

A starting behaviour equal to the normal conditions was found. It was decided to do a test with an electric controlled piston valve to investigate if i t would be possible to reduce the starting wind speed.

The electric controlled piston valve See drawing. cur-rent controlled by rotor speed electric magnet ~ +

iron piston

valv:e:t"1~~~

pump rod cylinder

rubber

The electric magnet keeps the piston valve open until the rpm counter gives the sign to loose the valve.

Then the windmill starts to deliver water.

The starting wind speed of the windmill is + 0,5 a 1 m/sec.

Water level 5,5 m~ below ground level. Reading water flow meter 1428 m~.

(25)

Date 1984.12 .. 07

We have changed the water measuring system. See drawing.

water inlet

\

concrete trough

water ~low meter

Benefits of this system

22

The time between pumping water and measuring water is reduced. Time is now ~ 5 a 10 sec. (more pressure over the water

meter) •

The total amount o~ water in the system is ~ar less than the other system ..

Date 1984.12.12

The filter in the return line is stopped up_

Water is running out the pressure vessel after cleaning i t is ok. Pressure height 3,5 meter.

Water level 5,5 below gorund level. Reading water flow meter 1443 m3 •

(26)

Date 1985.01.02

Because of frost the packing of the pump is broken. After mounting new packings the windmill is working ok. Pressure height 3,5 meter.

Stroke 100 mm.

Date 1985.01.10

23

Because of heavy frost the windmill was complete frozen. The pvc cylinder is frozen but not broken.

Date 1985.02.07

The wooden bearings of the rocker arm are clamping notwith-standing frequent lubrication.

After cleaning and new grease the wooden bearings are working ok. Cleaned the well of the CWD 2740.

Water level 0,2 meter below ground level (temporal). Reading water flow meter 1534 m3 •

Stroke 100 mm.

Date 1985.02.28

End of the frost period.

After mounting of the packings of the pump (they were pressed out by ice) the windmill is working ok.

Stroke 100 mm.

Date 1985.03.27

A new and larger electric magnet is mounted to enlarge the

attractive power to let the electric valve work in all conditions (high rpm).

After one cyclus of measurements the output seemed to have improved.

Measurements are going on (see report H. Oldenkamp, nr. R 765 D). Pressure height 3,5 meter.

Water level 5,0 m. below ground level. Reading water flow meter 1926 m3 •

Stroke 100 mm.

Date 1985.04.04

Replaced the reed switch of the rpm counter. The old one was worne.

Water level 5,5 meter below ground level. Reading water flow meter 2016 m3 _•

(27)

24

Date 1985.04.25

A stainless steel cylinder was mounted to investigate the influence of the friction between piston and cylinder.

Some experiments have been done with closing and opening of the piston valve with the help of the electric valve at preset times.

It is possible to find the max. cp eta curve.

(With the electric valve i t is possible to close the piston valve at a suction rpm and to open the valve at an other rpm.)

Pressure height 3~5 meter.

Water level 5,5 meter below ground level. Reading water flow meter 2218 m3 _•

Stroke 100 mm.

Date 1985.06.06

The friction between piston and stainless steel cylinder was measured by dismounting the rocker arm and pulling up the pump rod loaded with the water column.

Pressure height 3.00 meter. Water level 4,70 meter. Reading water flow meter. Stroke 100 mm.

Note: pressure height changed from 3,5 to 3 meter because there is running over water sometimes.

Probably the I" diameter of the pressure line gives so much resistance.

Date 1985.06.20

The stroke of the windmill was changed from 100 mm into 75 mm because of measurements. with the electric valve.

Date 1985.06.27

A pressure gauge on top of the suction air chamber was installed to obtain the pressure and under pressure in the air chamber. See drawing.

pressure gauge

cylinder

(28)

inlet--Pressure height 3,00 meter. Water level 4,70 meter. Reading water flow meter. Stroke 75 mm.

Pate 1985.08.08

The measurements were stopped for a period.

25

The pump was dismounted to remove the floating valve which was needed for measurements in the test rig at the laboratory of the

CWD.

See drawing. cylinder adjustable \ floating material \ \ leather cup

For exact specifications see drawing nrs. 8608-01.02.03. The valve floats when the windmill is standing still.

There is no resistance in the pump when the windmill is starting. At sufficient rpm of the rotor the water stream closes the valve by the under pressure caused by the water acceleration through the slit between piston valve and piston.

The under pressure moves the floating valve down to the piston. Then the windmill starts to deliver water.

(29)

26

Date 1985.10 .. 10

Measurements started with the floating valve in the windmill. The wooden bearings of the rocker arm and pump rod were cleaned and greased.

Pump height 3,00 meter.

Water level 1,80 meter below ground level. Reading water flow meter

Stroke 100 mm.

Date 1985.10.24

The measurements have been stopped because of overhaul of the measuring system at the testfield. (The signal cables of the windmills where damaged by rabbits.)

Date 1985.11.14

The measurements are started again.

A student is doing measurements on the dynamic behaviour of the windmill at several wind speeds.

The pump is working now with the floating valve.

The pressure vessel has been changed by a perspex one.

The pressure and suction line have been pulled back to the well of the

CWD 2000.

Pressure height 4 meter. Water level 1,80 meter. Reading water flow meter Stroke 100 mm.

Date 1985.12.07

The suction air chamber is changed by a perspex one so we can see what is going on in the air chamber.

See drawing.

-c:ylinder ylinder perspex c: ~ air chamber ~ air chamber / I

(30)

27

We have placed a measuring mast on the head of the windmill to measure:

- wind speed

- wind direction. See drawing.

hinged side vane

measuring mast

Pressure height 3,00 meter. Water level 1,80 meter. Reading water flow meter -Stroke 100 mm.

Experiments are going on. 4. A FEW REMARKS

\

,----~

rotor

One of the major problems of the CWD 2000 windmill is the wooden bearings of rocker arm and pump rod.

They need a special care and that is not a guaranty they will work ok.

The piston friction is a very important point for a small windmill

«

2,0 m).

The influence on the starting behaviour is very high. (See report R 765 D.>

Electric controlled piston valve.

The experiment with the electric controlled piston valve (which) in its turn simulates the floating valve) gave

promissing results with regard to pump starting at lower wind speeds.

5. CUMULATIVE MEASUREMENTS Not available.